In December 2024, Pan African acquired all the shares of Tennant Consolidated Mining Group (Tennant Mines), with Tennant Mines now being a wholly owned subsidiary of Pan African Resources.
- subscription is required.
Summary:
Tennant Creek Mineral Field (TCMF) is considered an iron-oxide copper gold deposit (IOCG) province and is host to high-grade deposits. The mineral deposits of the TCMF are hosted in rocks of the Warramunga province. The geology of the region comprises Paleoproterozoic sediments and intrusive suites that have been folded and faulted during several deformation events. An initial deposition of magnetite-hematite-quartz bodies (ironstones) formed hydrothermally into folds, cleavage planes and fault planes during early deformation. The zones are well defined within the TCMF.
Mineralisation is typically continuous in the short to medium range on strike, with long-range geological and grade continuity being experienced down-dip. Gold, copper and bismuth occur in the ironstones and gradually decrease in the surrounding chlorite alteration haloes. The mineralisation occurs as free-milling gold associated with fine-grained sulphides, mainly pyrite and chalcopyrite.
The TCMF is host to high-grade deposits such as Nobles, Juno, Warrego and Peko.
The TCMF mineralisation is contained within the iron oxide lode with a gradual decrease in economic mineralisation into the chloritised hanging wall and footwall lithologies. Gold, bismuth and copper mineralisation form a late-stage overprint on the hematite-magnetite lodes. Gold is typically concentrated towards the footwall of the ironstone or where the ironstone is in contact with chlorite and muscovite (Wedekind et al 1989). Economic enrichments of gold and copper are less evenly distributed compared to the ironstone, suggesting factors other than structure and stratigraphy are involved (Rattenbury 1992).
Nobles Gold Mine comprises several satellite deposits from surface stockpiles, open pit mines and underground operations such as the Black Snake, Chariot, Crown Pillar Stockpile, Eldorado, Golden Forty, Juno, Malbec, Mauretania, Nobles, Nobles North tailings, Rising Sun, Shaft 12, Weaber’s Find and White Devil deposits and other targets not reported as part of the Mineral Resources.
The mineralisation at Nobles is in magnetite-hematite-chlorite (ironstone) rock, with gold as the dominant economic commodity and subordinate copper and bismuth. Gold mineralisation occurs as lenses, typically (but not entirely) hosted by the east-west striking magnetite-hematite ironstone units. There is a clear zonation, with the core of massive magnetite-hematite-chlorite, surrounded by talc-magnetite, then dolomite. Faulting and shearing are very localised and, as such, have not been used to constrain the mineralisation and geological domains.
Rising Sun, Nobles, Eldorado, Mauretania, Chariot, Juno, Golden Forty and Black Snake are all broadly similar. All are iron-oxide gold deposits with high-grade gold mineralisation preferentially hosted within magnetite-hematite-chlorite ironstones. The ironstones are hosted within greywackes and siltstones of the Proterozoic Warramunga Formation. The ironstone orebodies form a cigar shape in section and are essentially lenticular in plan view. The orebodies average 10m to 50m wide with strike lengths of approximately 90m to 400m. The bodies tend to be aligned roughly east-west, lining up with the regional foliation. Locally, the ironstones can be elevated in copper and bismuth. An exception is Warrego, which has significant copper mineralisation associated with the gold. In the fresh rock, the mineral hosting copper is chalcopyrite, but this becomes oxidised to malachite and bornite in the upper weathered zones of the deposit.